1. Field of the Invention
This invention relates to an optical recording medium as well as to a method for conducting recording on said medium. More particularly, the present invention relates to an optical recording medium using, as its recording layer, a colored film formed by electrolytic polymerization to enable high density recording, as well as to a method for conducting recording on said medium.
2. Description of the Prior Art
For a recording medium called "optical disk" and capable of recording or memorizing a variety of information at a high density using a light such as a laser beam or the like, various types have hitherto been proposed. From the standpoints of low cost, high density recording, easy production, etc., many studies have been made on such recording media employing an organic material for its recording layer. Various recording media have been employed which comprises an organic material for the recording layer. The examples are the ones comprising a recording layer made of thermally softening or melting material provided over a colored layer for absorbing light to convert it to heat which are supported by a substrate such as glass, or the ones employing colored thermally melting material as a recording layer. In these recording media, the colored layer absorbs a laser beam (a recording light) and converts it to heat; the heat melts the colored layer or the recording layer formed thereon to cause partial deformation or removal of the layer; thereby information is recorded in the media.
As the coloring substance of the colored layer, there are used various dyes, pigments, inorganic substances having a color, etc. The colored layer is formed on the substrate by a method such as vacuum deposition or the like. The recording layer is formed on the colored layer by coating on the colored layer a thermoplastic resin (e.g. a polystyrene), a solution of a low-melting organic compound (e.g. n-hexatriacontane or zinc stearate), or the like. As the colored recording layer, there are used mixtures of a low-melting polymer or an organic compound as mentioned above and a dye or pigment.
The recording media comprising a recording layer made of a conventional organic material as mentioned above excel in that high density bit recording is easy, but simultaneously they have the following drawbacks. That is, the colored layer and the recording layer must be formed so as to be very thin and yet to have a uniform surface, which requires in their preparation the adoption of a costly thin film formation method such as a vacuum deposition method; this makes difficult the formation of a recording layer of large area although the formation of a layer of small area is relatively easy and, even if the recording layer of large area is formed, the layer has no uniform thickness; accordingly, the recording layer lacks reliability in performances of recording, reading-out, etc. In addition, the stability of the recording layer and of the information recorded therein when stored over a long period of time is insufficient.